Report of the SC-04-04 Working Group on Microphone Measurement and Characterization of the SC-04 Subcommittee on Acoustics meeting, held in Paris, France, 2006-05-21

The meeting was convened by chair D. Josephson.

The agenda and the report of the previous meeting, held in New York, 2005-10-08, were approved as written.

Open Projects

AES42-R, Review of AES42-2006: AES Standards for Acoustics - Digital interface for microphones
Noting that the Call for Comment for the revision of AES42-2001 was still open, there was no discussion on that draft. There was discussion about including digital mic splitters in a subsequent revision.

Development Projects

AES-X093, Recommendations for Revisions of IEC 61938 Clause 7
There was discussion on the upcoming revisions for the phantom power specifications in IEC 61938 (Audio, video and audiovisual systems - interconnections and matching values - preferred matching values of analogue signals) and also IEC 60268-4 (Sound system equipment - Part 4: Microphones). We are able to provide input to IEC TC100 through member J. Woodgate, who is responsible for maintenance of these standards. There are some errors to resolve in IEC 60268-4 and some simplification in IEC 61938 when the time comes to make a recommendation on these revisions. There does not appear to be support for the previously discussed performance standard for phantom power (that a multi-input device with phantom power should be able to power microphones connected to all inputs simultaneously, or label the device advising the user of the limitation to such operation).

AES-X085, Detailed Professional Microphone Specifications
Work continues on the project AES-X085 within task group SC-04-04-E. Because of the general interest in this work, task group leader David Josephson has been holding meetings concurrently with the working group meetings, which was again the case with this meeting. Since the previous meeting, E.B. Brixen from DPA has produced a standard noise test source which could be evaluated by each of the labs participating in AES-X085 to see whether we can reach consensus on a testing method. No report was available on the progress of these tests.

Along with the discussion of detailed professional microphone standards as part of AES-X085, there had been some discussion on the email reflector on maintenance of several retired DIN performance standards. This was discussed at some length during the meeting and there did not appear to be much support among members for a standard that would impose a performance criterion. In general, the opinion of most members was that the audio market had changed substantially in the past few years, and this change has reduced the overall level of technical education and awareness among microphone buyers. As a result, microphone makers consider that more detailed or stringent specifications would not help them in the marketplace, and as a result they are not interested in developing such standards.

New projects

No new projects were requested.

New business

There was no new business.

The next meeting will be scheduled in conjunction with the AES 121st Convention in San Francisco, CA., US. in 2006-10